Geological and geophysical modeling tools allow a user to select a line of wells (usually referred to as a Cross-section) and then to mark characteristics or pick formation TOPS. These modeling tools are used by the energy and natural resource conservation and development enterprises to characterize wells and make predictions about available reserves.
Without automated tools, earth scientists start with a paper well log and pin it to a board. The well log shows measurements of the well charted along its depth. A paper well log is printed on a long roll of paper with several different parameters charted down the length of the paper. The parameters are aligned by depth so that at any one depth, the scientist can see values for each parameter together.
For comparison the earth scientist selects a log from any adjacent or nearby well and pins it next to the first well to compare characteristics of the two wells. Both paper logs can be marked and commented at interesting points for future reference. Another log can be selected from another well adjacent to the first well (but in a different direction) and the same kind of comparisons can be done.
From these manual methods, a workflow developed based on the concept of pinning a log. The first log is identified as being pinned to the board and then the other logs are compared to the pinned log. The comparisons to the pinned well happen for as many wells as are available near the first pinned well. If there is a second well that looks as though there is a formation of interest between it and the first pinned well, then the researcher can pin the second well's log to the board as the new reference. Comparisons can then work out radially or in any other direction from that well. In this manner, a geological formation can be followed at any depth through a line of wells that was not predetermined before the professional started working.
Automated tools for comparing logs have diverged from the traditional workflow and can be difficult to use. A further problem for automated tools is in supporting the comparisons. Many of the comparisons involve marking and commenting individual formations through which the well log passes. When an earth scientist selects a well and clicks on a log image or a particular data curve on a log, it is often to mark a depth or indicate a new formation top. While the depths are typically well marked, there can be many different tops to pick for each well, and there can be many wells. Choosing names of tops or formations from a list is helpful but the lists can become cumbersome as well.
Choosing names of tops to associate with a well becomes easier, if there is a list of formations set up initially. While this can make it somewhat easier to pick tops using the list, establishing the list can be cumbersome and ordering the list can be worse. Formations do not always occur in the same order in every well and there can be many different formations through the entire depth of the well.